what your father is complaining is may be lactose intolerance
. Many people can digest milk or milk products, they becaome uneasy after consumption of milk which is termed as lactose intolerance.
Milk is not the only source of calcium, you can opt for calcium rich fruits like custard apple,almonds, tofu, sesame seeds,flax seeds, brazil nuts and green leafy vegetables.
These all are heart freindly foods too.
His BP 130/80 is good, there is nothing to worry. To prevent him landing into hypertension
you can change his diet pattern like linit the salt intake, limit the oil intake 3-4teaspoons of oil per day, have more vegetables and fruits, opt for lean meat etc, ask him to stop smoking
and drinking if he does so.
and a simple walk for 30 min everyday.
All these things will solve your problems.
I hope this answers your question.
Wish you and your father good health.